Improvement in safety-valves



GEORGEW. CSHING, OF CHICAGO, ILLINOIS, -ASSIGNORTO HIMSELF AND HORATIO ANDERSON, OF SAME PEACE.

Letters Patent No. 99,762,

dated February 15, 1870.

IMPROVEMENT IN SAFTY-VALVES.

To all whom vit-mcy concern:

Be it k nown that l, GEORGE W. CUSHING, of Chicago, in the county ot' Cook, and State of Illinois, have invented a new and useful Improvement in Spring-Loaded Safety-Valves for-Steaxn Generators; and l do ,hereby declare the following to be a full, clearrandrexact description thereof, which will enable others skilled in the art to which my .invention appertain's to makepand use the same, reference being had to theaccoinpanying drawings, forming part of this specification, in which- Figure l is a side elevation of the enclosing case of my improved safety-valve;

Figgre 2 is. a vertical longitudinal section ofthe same;

Figure 3 is a detail bottom view of the enclosing oase;

Figure 4 is a detail top plan view of the guard 'for relieving the valve of the weight of the liftingbar;

Figure 5 is a detached view of the valve and lifting bar; y

Figure 6 .shows a sectional and topplan view of the valve detached from the case; and

lFigure 7 a plan view of the lower guard or guide for the valve.V Y

Similar letters of reference indicate corresponding parts in the several figures of the drawings.

My invention relates to that class of steam-valves known as spring-loaded safety-valves, and has for its object to improve the construction of the valve patented by H. Anderson, February 18, 1868, No. 74,480.

My invention consists, irst, in the combination with the valve-stem depending from the under side of the valve and wit-l1 the seat which forms the bearing surface for the spring, of a cone-shaped steel spring, having its coils made of angular metal' in cross-section, whereby the saine is easily constructed and kept constantly clean by the action ofthe steam upon the coils.

l am aware that volute springs have been used in this connection, but they are diliieult of construction, requiring the exercise of great skill, and are, consequently, expensive. In use, also, they become clogged by incrustations, and are, therefore, unreliable in their operation.

1t ctnsists, secondly, in the valve-stein or spindle provided with a collar to support the cone-shaped spring, with a projection below the collar which enters a guard placed within the steam-pot, to hold the valvestem in a central position within the steam-pot, and

finger with the valve-stem and graduated valve, to determine the pressure of steanrrequired to litt the valve.

. It consists, fourthly, in the combination of a guard with the valve-stem and valve-lifting bar, to relieve the valve of the weight of said lifting bar.

- It consists, ifthly, in the Vcombination of a guide with the valve-stem and steam-pot, to guide the valvestem centrally within the steam-pot, and thus permit the valve lto fit snugly upon its seat.

It consists, last-ly, in the peculiar construction of the steam dome and the method of attaching the'same to the steam pot, as will be hereinafter more fully described.

In the accompanying drawingsv B is the valve-stem, to which the valve is fitted by means of a screw-thread, in a manner similar to an ordinary bolt and nut.

The valve A rests upon the seat K, and the stem project-s below the seat into the steam-pot or-case'N, which is attached in any suitable manner to asteam generator, and to which the valve-seat K is secured by means Aof the bolts R. Y

' G is the coiled spring placed below the valve around the stem B. It is made in the form of an inverted cone, and is held in place by the collar C near the lower end ofthe v'valve-stem, and the downward .projection L formed upon the under side of the valve-seat K.

As the spring is composed of angular metaldisposed in vspiral coils, it can be constructed by ordinary mechanics, and therefore produced cheaply. VThe distance between the coils is such that the steam in its passage around the valve comes iu contact with every part of' the spring, and therefore keeps the latter constantly clean and free from incrustations.

I D is a projection formed below the collar C, in continuation of the valve-stem, andis adapted to lit with easy contact within a guide-frame, H, placed in the lower end of the steam-pot. By this arrangement the valve-stem is guided centrally within the .steam-pot and the' valve A consequently made to t its seat equally upon all sides. The pressure of steam required to lift the valve `is governed by the tension of the spring, and the tension ofthe spring is adjusted! to greater or lesser pressure by moving the valve up or down upon the valve-stem. When the desired tension has been obtained the valve is locked in position by means of the lock-nut E, as shown. The upper side of the valve is provided with a squared projection, a, shown in tig.,6, to receive a wrench for turning ,the same.

P is an index-finger, attached in anyl suitable manner to the valve-stem above the valve, and extending over the graduated upper surface of the latter, as shown' in iig. '6. By this arrangement the-exact pressure of steam reqniredto lift the valve is indicated as the valve is turned to adjust the tension of the spring Gr The register upon the upper surlace of the valveis indicated by graduated concentric circles, thegures indicating the different pressures. For example, the first turn of the valve will indicate, by the index-1inger, twenty pounds on the outer circle, the second turn thirty pounds, and so on to the maximum pressure.

From the foregoing description it will be understood that a simple and eEective safety-valve is produced.

In order to enclose the same in such a manner that after having been set to the predetermined pressure, it cannot bechanged or tampered with from the outside, l provide a case or dome, M, which eucloses the up per portion of the valve, and is secured to the Valveseat K and steam-pot N by means of the1ockbo1ts R R. rllhe dome M is also provided along its lower edge witk a flange or ring, U, which covers the joint formed by the connection ofthe dome with the valve-seat and steam-pot. I

The lock-bolts R are provided with holes T above the nuts S, for the reception of padlocks, wires, orother devices which may be employed as seals or for the purpose of security.

'llie upper end of the dome M is formed or provided with a chamber divided into three or more divisions, in which the steam passages occupy reverse positions relatively to each other, to prevent any instrument being inserted through the discharge-opening O to turn the valve.

` J is a bar extending vertically through the steamdome M, and is designed to afford means for testing the valve under pressure. It is flattened, to prevent turning and save space, and fits with easy contact the partitions which iormvthe chambers O 0. Its lower end forms a yoke fitting over the upper end of the valve-stern, and is held upon said valve-stem by the jam-nuts E l". To the upper end of the bar any suitable device may be attached for lifting the valve, so

that a proper application of force will counterbalance the tension pressure of the spring G, and permit the opening of the valve witha minimum pressure of steam in the steam-pot N.

To prevent the lifting bar from ,being forced down upon and. thereby increase theload of the valve, I introduce a guard-frame, I, shown in fig. 2, between the valve and lower end of the yoke, with its legs Z clamped between the valve-seat K and dome M, as shown. lllhis guard, while it supports the lifting bar above the Valve, does not interfere with the requisite movement of the valve-stem.

As the spring G is at all times exposed to the action of the steam in the pot N, it will at any given pressure indicate a uniform elasticity. The course of the steam is shown by the arrows, tig. 2.

From the foregoing the operation of my improved safety-valve will be readily understood without further description.

Having thus described my invention,

What I claim as new, and desire to secure by Let-4 ters Patent, is-

1. The combination with the valve-stein B and" spring-seat L, the inverted cone-shaped coiled spring G, constructed and arranged as herein shown and described, for the purpose specified.

2. The screw-threaded valve-stem B, provided with the collar C, guide D, and lock and jam-nuts E F, as herein shown and described, for the purpose specified.

3. The combination of the index-finger I with the valve-stem B and graduated valve A, substantially as described, for the purpose specified.

4. The combination of the guard I placed within the dome with the valve-stein B and lifting-bar J, sub stantially as described, for the purpose specied.

5. The combination of the guard H with the projection D of thevalve-stem, and guiding the same and lower end of the steam-pot N, substantially as described, for the purpose specified.

6. A steam-dome, for convertinga safety-valve into a lock-valve, provided with a series of chambers or pipes having their discharge-openings in reverse positions with relation to each other', substantially as described, for `the purpose specified.

7. A steam-dome, for converting a safety-valve into a lock-valve, provided with a projecting flange, rim, or ring, to enclose thejoints formed by the connection of said dome tothe valve-seat and steam-pot or valvecase, substantially as described.

8. The combination of the steam-dome M and valve and spring-seats K L and the steam-pot N, when constructed as shown and connected ltogether by means of the lock-bolts It and nuts S, substantially as herein described, for the purpose specified.

GEO. NV. CUSHING.

Witnesses:

D. I. POWERS, WM. C. FABWELL. 

